user: Question: On what date was Stauffer Chemical Company (LeMoyne Plant), which was listed on 09/21/1984, deleted?
Columns: ['CERCLIS ID', 'Name', 'County', 'Proposed', 'Listed', 'Construction completed', 'Partially deleted', 'Deleted']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['AL6210020008', 'Alabama Army Ammunition Plant', 'Talladega', '10/15/1984', '07/22/1987', '–', '–', '–']
SQL:

assistant: SELECT "Deleted" FROM "Table" WHERE "Listed" = '09/21/1984' AND "Name" = 'Stauffer Chemical Company (LeMoyne Plant)';