LEAD: S. Korea's ex-Unification Minister Chung chosen to run for president

(EDS: ADDING DETAILS)

South Korea's former Unification Minister Chung Dong Young was chosen Monday to run in the Dec. 19 presidential election from the pro-government United New Democratic Party.

Chung, a former television anchor, is expected to face a difficult race as former Seoul mayor Lee Myung Bak, the front-runner from the opposition Grand National Party, is enjoying a solid lead with an approval rating of over 50 percent.

In a party convention held in Seoul, the 54-year-old Chung won the race with about 210,000 votes, defeating former Gyeonggi Gov. Sohn Hak Kyu who got about 160,000 votes and former Prime Minister Lee Hae Chan with about 110,000 votes.

In his acceptance speech, Chung called for unity among party members to win the presidential election.

''I am completely confident that victory will be ours in December if we become one,'' Chung said.

Chung said the nation faces ''changes and new choices'' and he vowed to bring about ''big changes'' that the people want.

President Roh Moo Hyun, whose five-year single term is to expire in February next year, is not allowed under the Constitution to seek a second term.

Various opinion polls show voter sentiment has clearly turned in favor of the opposition candidate mainly due to the current government's alleged mismanagement of economic affairs and policy flip-flops.