Table: clarkson_bridge
Columns: name
built
listed
location
county

Question: When was the oakachoy covered bridge listed?
SQL: SELECT "listed" FROM clarkson_bridge WHERE "name" = 'oakachoy covered bridge'

Question: In which county is the swann covered bridge located?
SQL: SELECT "county" FROM clarkson_bridge WHERE "name" = 'swann covered bridge'

Question: Which bridge is located in Nectar, in Blount County?
SQL: SELECT "name" FROM clarkson_bridge WHERE "county" = 'blount' AND "location" = 'nectar'

Question: Which county built a bridge in 1934?
SQL: SELECT "county" FROM clarkson_bridge WHERE "built" = '1934'

Question: In which year did Blount County build a bridge in Cleveland that was listed on 1981-08-20?
SQL: SELECT "built" FROM clarkson_bridge WHERE "county" = 'blount' AND "listed" = '1981-08-20' AND "location" = 'cleveland'