CREATE TABLE table_name_68 (goals_against INT, goals_for VARCHAR, goal_difference VARCHAR)

What is the average of goals against, where overall goals are more than 35 and the goal difference is 20?
SELECT AVG(goals_against) FROM table_name_68 WHERE goals_for > 35 AND goal_difference = 20
SELECT AVG("goals_against") FROM "table_name_68" WHERE "goal_difference" = 20 AND "goals_for" > 35