Katie Hill, Democrat running for California's 25th Congressional district seat in Congress, speaks during the opening of the SCV Democratic Headquarters for 2018 in Newhall, Calif., on Saturday, May 26, 2018.

Democrat Katie Hill, a political newcomer, is the apparent winner in her challenge of two-term Rep. Steve Knight in a closely watched race in Southern California's 25th Congressional District, according to NBC News.

Hill's apparent victory is another seat gain for Democrats as they look to pad their projected House majority.

Hill, a former head of a nonprofit that assists homeless people, crushed Knight in fundraising during the heated campaign by raising nearly $6.3 million, or about three times the amount the incumbent collected. About $3.8 million was raised in the third quarter alone by the Democrat, while Knight's campaign took in less than $460,000 in the period.

The 25th District, where Democrats hold a nearly 4-point edge in voter registration, stretches from northern Los Angeles County into a portion of eastern Ventura County. Democratic presidential candidate Hillary Clinton carried the working-class district in 2016.

During the campaign, Hill took on Knight's record on immigration as well as his support of the GOP tax plan and repeal and replacement of Obamacare. Knight tried to distance himself during the campaign from President Donald Trump, particularly on immigration matters.

Hill, who was endorsed over the summer by former President Barack Obama, identifies herself as bisexual and made LGBTQ rights a part of her platform.