Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_2147588_4 (district VARCHAR, successor VARCHAR)
### Question:
When william b. campbell (u) is the successor what is the district?
### Answer:
SELECT district FROM table_2147588_4 WHERE successor = "William B. Campbell (U)"