user: Question: What is the highest diff with drawn of 6 and play larger than 18?
Columns: ['Team', 'Points', 'Played', 'Drawn', 'Lost', 'Against', 'Diff']
Types: ['text', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: ['U.A. Maracaibo', 41.0, 18.0, 5.0, 1.0, 11.0, 17.0]
SQL:

assistant: SELECT MAX("Diff") FROM "Table" WHERE "Drawn" = 6.0 AND "Played" > 18.0;