Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the lowest goals against value for a team with 83 points and a difference over 50?

### Inputs:
table_name: table, columns: ['Season', 'Belonging league', 'Matches', 'Points', 'Draw', 'Lose', 'Goal difference', 'Goals For', 'Goals Against', 'Position']

### Response:
SELECT MIN Goals Against FROM table WHERE Points = 83 AND Goal difference > 50