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

### Instruction:
List the number of builders where the withdrawn is 1951 and number is 42.

### Inputs:
table_name: table, columns: ['Date', 'Builder', 'Type', 'Operator', 'Number', 'Withdrawn', 'Status']

### Response:
SELECT COUNT Builder FROM table WHERE Withdrawn = 1951 AND Number = 42