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

### Instruction:
What's the exponent field that has 255 exp and value of +∞?

### Inputs:
table_name: table, columns: ['Type', 'Actual Exponent', 'Exp (biased)', 'Exponent field', 'Significand (fraction field)', 'Value']

### Response:
SELECT Exponent field FROM table WHERE Exp (biased) = 255 AND Value = +∞