PHOENIX — Former Democratic state Sen. Kyrsten Sinema has been elected to represent a new Phoenix-area congressional district, emerging victorious after a bitterly fought race that featured millions of dollars in attack ads.

Sinema becomes the first openly bisexual member of Congress. Her victory came in a year when three states approved gay marriage, and at least five openly gay Democrats were elected to House seats. A Wisconsin congresswoman also became the first openly gay person elected to the Senate.

Sinema had a narrow lead on election night that made the race too close to call. But she slowly improved that advantage as more ballots were tallied in recent days, and now has a nearly 6,000-vote edge that is too much for Republican Vernon Parker to overcome.

One other congressional race remains undecided in Arizona. Rep. Ron Barber, the hand-picked successor to Gabrielle Giffords, had a lead of a few hundred votes over Republican Martha McSally in the Tucson-area district.