LOS ANGELES – Mayor James Hahn struggled to hold on to his office yesterday against Antonio Villaraigosa, a charismatic councilman seeking to become the first Hispanic mayor in more than a century in a city that is now nearly 50% Latino.

The bruising runoff between the two Democrats was a rematch of the 2001 election, in which Mr. Hahn rallied to defeat Mr. Villaraigosa and win his first term as mayor of the nation’s second largest city.

Mr. Villaraigosa came back strong this year, nearly ousting Mr. Hahn in the March primary and holding a double-digit lead in recent polls. But an expected low turnout made the outcome unpredictable.

Mr. Villaraigosa, a high school dropout and immigrant’s son from the barrio who rose to speaker of the state Assembly, was seeking to become the first Hispanic mayor in Los Angeles since 1872. Mr. Hahn, the scion of a prominent political family, was in danger of becoming the first Los Angeles mayor in 32 years to be bounced from office.

Elsewhere, Pittsburgh held a primary for mayor with the city mired in worst financial crisis since the collapse of the steel industry during the 1980s. And voters in Dover, Pa., picked their candidates for the school board in a community that has been roiled by a new and apparently first-in-the-nation policy requiring that students learn about the “intelligent design” theory of creation.

Mr. Hahn, 54, saw his first term hampered by corruption allegations against his administration.

Mr. Villaraigosa, 52, tried to capitalize on those allegations. But he was forced under pressure to return nearly $50,000 in donations from employees of two companies with possible interests in airport concession contracts.

Political strategist Darry Sragow said that after a torrent of negative TV advertising, the race was about “who is the least dirty.”

Mr. Hahn’s family has been active in Los Angeles politics for decades; his father, Kenneth, was a beloved county supervisor. He touted Los Angeles’s dropping crime and argued that he is the man to cure such urban ills such as failing schools and gridlock.

But the coalition of blacks and moderate-to-conservative San Fernando Valley voters that put him in office four years ago broke apart this time. He lost black support because he backed the ouster of Police Chief Bernard Parks, who is black.

And Mr. Hahn’s lawyerly – some say drab – image left him open to criticism that he isn’t up to being the public face of star-studded L.A.

For his part, Mr. Villaraigosa positioned himself as a unity candidate who would bridge racial and ethnic groups in a city that is 48% Hispanic, 31% white, 11% Asian and 10% black. He lined up marquee endorsements from John Kerry to basketball legend Magic Johnson.

Yesterday, Jesse Sanders, a 75-year-old black man, said he voted for Mr. Hahn because he considered him the lesser of two evils.

“It was a negative campaign as far as I’m concerned. The issues weren’t dealt with,” Mr. Sanders, a retired probation officer who cast his vote in South Los Angeles, said.