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_38 (year_built VARCHAR, length VARCHAR)
### Question:
Where the length is 91', what is the year built?
### Answer:
SELECT year_built FROM table_name_38 WHERE length = "91'"