user: Question: What is Date, when Competition is "F", and when Opponents is "FC Astoria Walldorf"?
Columns: ['Date', 'Venue', 'Opponents', 'Score', 'Competition', 'Match Report']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['July 5, 2008', 'Am Steinchen, Grävenwiesbach', 'Hochtaunus XI', '11-0', 'F', 'eintracht-archiv.de']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Competition" = 'F' AND "Opponents" = 'FC Astoria Walldorf';