SCHEMA:
CREATE TABLE table_name_57 (goals_against INTEGER, draws VARCHAR, wins VARCHAR, goal_difference VARCHAR)
USER:
What is the high goal against associated with 18 wins, a Goal Difference of 43, and under 6 draws?

QUERY:
SELECT MAX(goals_against) FROM table_name_57 WHERE wins = 18 AND goal_difference = 43 AND draws < 6