The race for California’s 25th Congressional District, representing Santa Clarita, Simi Valley and much of the Antelope Valley, is a top target for Democrats hoping to gain control of the House of Representatives. It’s the only Republican-held congressional seat in Los Angeles County.

The area turned away from its historically white, conservative leanings as the housing crisis began forcing a more diverse group of residents of the L.A. area out into the high desert a decade ago, the Los Angeles Times reports. The district went to Hillary Clinton in 2016 by nearly 7 points, and Democrats now have an edge in voter registration.

Democrat Katie Hill, a political newcomer, is promising to end politics as usual in her bid to unseat Rep. Steve Knight, a Republican elected to Congress in 2014 after serving in the state Legislature.

Hill, 31, is a former executive at a Los Angeles homeless services nonprofit. She grew up in the area and lives on a ranch in Agua Dulce.

Knight, 51, is a former Los Angeles police officer and Army veteran who turned to politics initially as a Palmdale City Council member.

The race has seen an influx of cash, much of it in support of Hill, whose campaign has raised nearly three times as much as Knight. It’s one of the costliest races in the U.S.

Read more on the issue-by-issue differences between Hill and Knight here.