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_name_89 (entered_service VARCHAR, locomotive VARCHAR)
### Question:
How many years entered service when there were 13 locomotives?
### Answer:
SELECT COUNT(entered_service) FROM table_name_89 WHERE locomotive = "13"