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_78 (built VARCHAR, location VARCHAR, county VARCHAR, listed VARCHAR)
### Question:
In which year did Blount County build a bridge in Cleveland that was listed on 1981-08-20?
### Answer:
SELECT built FROM table_name_78 WHERE county = "blount" AND listed = "1981-08-20" AND location = "cleveland"