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

### Instruction:
What is Points Difference, when Points Against is 451?

### Inputs:
table_name: table, columns: ['Club', 'Played', 'Drawn', 'Lost', 'Points for', 'Points against', 'Points difference', 'Bonus Points', 'Points']

### Response:
SELECT Points difference FROM table WHERE Points against = 451