user: Question: What date was the opponent in the final Barbara Paulus?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['4 July 1988', 'Båstad , Sweden', 'Clay', 'Sandra Cecchini', '7–5, 6–1']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Opponent in the final" = 'Barbara Paulus';