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

### Instruction:
On which date was the class 157?

### Inputs:
table_name: table, columns: ['Class', 'Date', 'Builder', 'No. built', '1919 nos.', 'LMS Class', 'LMS nos.']

### Response:
SELECT Date FROM table WHERE Class = 157