Progressive Party Rep. Kang Sung-hee celebrates his by-election victory on Wednesday. (Yonhap)

The minor Progressive Party, deemed to be more left-wing than the National Assembly’s majority-holding Democratic Party of Korea or the Justice Party, has returned to the National Assembly.

The party’s Rep. Kang Sung-hee won 39 percent of the votes in Jeonju, a liberal constituency in North Jeolla Province, in a by-election on Wednesday, beating her Democratic Party-affiliated rival, who earned 32 percent.

It took the Progressive Party, which was the Unified Progressive Party in a former incarnation, seven years since disbandment to win a seat in the National Assembly.

The party is composed of some key officials from the now-defunct Unified Progressive Party, which was disbanded in December 2014 by the Constitutional Court for its close alignment with North Korea. Also in 2014, the Unified Progressive Party’s Rep. Lee Suk-ki was handed 12 years’ jail term for insurrection.

After Wednesday’s victory, some critics took issue with the newly elected Progressive Party lawmaker’s remarks over the election race.

In a televised debate on March 27, he said that “from North Korea’s perspective, firing missiles is exercising the right to self-defense” while discussing North Korean military provocations. He stressed South Korea’s sovereignty in the context of its alliance with the US.

The lawmaker is speculated to be a part of the Assembly’s committee for national defense, which is currently short of members.

Kang, in response to criticisms that he is ill-fit to serve on the national defense committee because of his views, said in a statement Friday that “the idea that a lawmaker can or cannot be on a certain committee is anti-Constitutional and anti-parliamentarian.”

“Whichever committee that I am assigned, I am prepared to do my very best to serve the people who have chosen me,” he said.

Kang began his term Thursday.

On Wednesday, the chief of the Progressive Party’s committee in Jeju Island was indicted on charges of aiding a North Korean spy ring.