user: Question: What date was the Bronze label in vinyl format?
Columns: ['Date', 'Region', 'Label', 'Catalogue', 'Format']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['27 June 1981', 'UK', 'Bronze', 'BRON 535', 'vinyl']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Label" = 'Bronze' AND "Format" = 'vinyl';