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 (transfer_window VARCHAR, transfer_fee VARCHAR, moving_to VARCHAR)
### Question:
What Transfer window that has a Transfer fee of free, with a Moving to of derby county?
### Answer:
SELECT transfer_window FROM table_name_54 WHERE transfer_fee = "free" AND moving_to = "derby county"