INDIANAPOLIS (AP) — In an election year dominated by calls for change, Indiana's congressional delegation didn't.

All nine of Indiana's congressmen retained their seats Tuesday, although some margins of victory may have been a little closer than some incumbents would have hoped.

"All of those winners are now breathing a sigh of relief," said James McCann, a political science professor at Purdue University.

Democrat Mike Montagano, a 27-year-old lawyer, failed to unseat Republican Rep. Mark Souder, who was first elected to the Republican-leaning 3rd District in northeast Indiana in 1994. National Democrats had spent heavily in support of Montagano, with television commercials attacking Souder as a Washington insider and touting Montagano as an abortion opponent who favors gun rights. But it wasn't enough for a Montagano win.

Souder ended up with 55 percent of the vote, according to unofficial results tabulated by The Associated Press. Souder typically wins by more than 60 percent, but was held to 54 percent of the vote in 2006.

Montagano was pleased with how far his campaign had come, even though he was disappointed by the loss, said campaign manager Daynan Crull.

"This was one of the most competitive, toughest-fought battles, I think, in the country," he said.

Democratic challenger Nels Ackerson, a lawyer and former aide to Sen. Birch Bayh, ran an active campaign against Republican Rep. Steve Buyer. But Buyer got 60 percent of the vote to win a ninth term in the Republican-leaning 4th District, according to AP tallies. That's a comfortable margin but marks the fewest percentage of votes Buyer has earned in a general election since he was first elected in 1992 with 51 percent of the vote.

Buyer said support for Democratic presidential candidate Barack Obama may have had an effect on the race, but he said voters are comfortable with him.

"They know me, and I know them," Buyer said.

The closer-than-usual margins of victory in the 3rd and 4th districts were a sign of serious challengers boosted by Democratic momentum, McCann said.

"The lesson those incumbents learned is that they dodged a bullet," McCann said.

Freshmen congressmen are typically easier targets for challengers. But Indiana's three new Democratic congressmen easily won re-election.

Democratic Rep. Joe Donnelly defeated Republican business-owner Luke Puckett, who was making his first run for public office in northern Indiana's 2nd District. In the 7th District in Indianapolis, Rep. Andre Carson beat GOP challenger Gabrielle Campo, a social worker who entered the race after the primary winner dropped out. And Rep. Brad Ellsworth in southwest Indiana's 8th District defeated Republican Greg Goode, a former congressional aide who struggled to raise campaign cash.

Democratic Rep. Baron Hill in southeast Indiana's 9th District won his rematch with former Rep. Mike Sodrel, a Republican and trucking company owner. The two have faced off in four consecutive elections, with Hill defeating Sodrel in 2002, then losing to him in 2004 before reclaiming the seat in 2006. Hill won 57 percent of the vote this year, according to AP results.

"I have known victory and I have known defeat," Sodrel said. "I am at peace with the outcome."

Democrat Pete Visclosky won a 13th term in the heavily Democratic 1st District in northwest Indiana, and Republican Reps. Dan Burton and Mike Pence retained their seats in the 5th and 6th districts, respectively.