user: Question: What is the lowest goals against value for a team with 83 points and a difference over 50?
Columns: ['Season', 'Belonging league', 'Matches', 'Points', 'Draw', 'Lose', 'Goal difference', 'Goals For', 'Goals Against', 'Position']
Types: ['real', 'text', 'real', 'real', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: [2007.0, 'JFL', 34.0, 83.0, 5.0, 3.0, 50.0, 81.0, 31.0, 1.0]
SQL:

assistant: SELECT MIN("Goals Against") FROM "Table" WHERE "Points" = 83.0 AND "Goal difference" > 50.0;