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

### Instruction:
When william b. campbell (u) is the successor what is the district?

### Inputs:
table_name: table, columns: ['District', 'Vacator', 'Reason for change', 'Successor', 'Date successor seated']

### Response:
SELECT District FROM table WHERE Successor = William B. Campbell (U)