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_54 (longitude VARCHAR, diameter__km_ VARCHAR)
### Question:
What shows for the Longitude when there is a Diameter (km) of 31km?
### Answer:
SELECT longitude FROM table_name_54 WHERE diameter__km_ = "31km"