CREATE TABLE table_50373 ("Name" TEXT, "Date" TEXT, "Goals" FLOAT, "Assists" FLOAT, "Team" TEXT, "Venue" TEXT, "Opponent" TEXT, "Competition" TEXT, "Total Gs" FLOAT, "Total As" FLOAT)

How many assists were in the k-league competition, which has more than 20 total Gs, the pohang steelers team, and chunnam dragons as the opponent?
SELECT "Assists" FROM table_50373 WHERE "Competition" = 'k-league' AND "Total Gs" > '20' AND "Team" = 'pohang steelers' AND "Opponent" = 'chunnam dragons'
SELECT "Assists" FROM "table_50373" WHERE "Competition" = 'k-league' AND "Opponent" = 'chunnam dragons' AND "Team" = 'pohang steelers' AND "Total Gs" > '20'