user: Question: What is Surface, when Date is less than 1979, and when Opponent in the Final is "Bill Scanlon"?
Columns: ['Outcome', 'Date', 'Championship', 'Surface', 'Opponent in the final', 'Score in the final']
Types: ['text', 'real', 'text', 'text', 'text', 'text']
Sample row: ['Runner-up', 1978.0, 'Maui , U.S.', 'Hard', 'Bill Scanlon', '2–6, 0–6']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Date" < 1979.0 AND "Opponent in the final" = 'Bill Scanlon';