LOS ANGELES — Democrat Katie Hill has captured the last Republican-held U.S. House seat anchored in Los Angeles County. Hill ousted Republican Rep. Steve Knight, who was seeking a third term in the 25th District that cuts through suburbs, horse ranches and high desert in northern Los Angeles County and a slice of Ventura County. Knight conceded the race earlier this week. Hill maintained her election night lead after further vote counts were released Friday. The victory will pad the Democratic advantage in the House next year. A political newcomer, Hill has stressed her centrist politics. She’s a gun owner and her Republican father is a police officer who had never voted for a Democrat before her primary. Her mother, a Democrat, is a nurse.