CREATE TABLE table_43980 ("Season" FLOAT, "Team 1" TEXT, "Score" TEXT, "Team 2" TEXT, "Venue" TEXT)

What year did Bangkok University and Chunnam Dragons have a score of 0-0?
SELECT SUM("Season") FROM table_43980 WHERE "Team 1" = 'bangkok university' AND "Score" = '0-0' AND "Team 2" = 'chunnam dragons'
SELECT SUM("Season") FROM "table_43980" WHERE "Score" = '0-0' AND "Team 1" = 'bangkok university' AND "Team 2" = 'chunnam dragons'