Korean-American Democrat Andy Kim has been elected to the U.S. House of Representatives, becoming the first Korean to serve in Congress in almost 20 years.

His opponent, incumbent Rep. Tom MacArthur posted on his Facebook Wednesday night that he had called Kim to concede, writing that "enough provisional ballots have been counted to make the outcome clear."

The Associated Press had officially declared Kim the winner earlier Wednesday, though the local election boards have not completed counting provisional ballots. 

The result comes eight days after the U.S. midterm elections last Tuesday.

Kim is the second U.S. congressional member of Korean descent after Jay Kim, who served in the House of Representatives between 1993 and 1999.

Another Korean-American, Young Kim, a Republican candidate for California's 39th Congressional District, remains in a tight contest. 

According to CNN on Wednesday, Kim was leading Democrat Gil Cisneros with a narrow margin of point-four percentage point or 711 votes as of Wednesday. 

If elected, she will become the first Korean-American woman to serve in Congress.