Table schema:
CREATE TABLE table_name_12 (goals_against INTEGER, draws VARCHAR, wins VARCHAR, points VARCHAR, goal_difference VARCHAR)

Question: What is the highest goals against when points are larger than 31, the goal difference is smaller than 9, wins are 13, and draws are larger than 6?
SQL: SELECT MAX(goals_against) FROM table_name_12 WHERE points > 31 AND goal_difference < 9 AND wins = 13 AND draws > 6