user: Question: For the tournament played on a Hard surface and ending with a score of walkover, who was the Finals opponent?
Columns: ['Date', 'Tournament', 'Surface', 'Opponent in the final', 'Score']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['July 26, 1993', 'San Juan , Puerto Rico', 'Hard', 'Ann Grossman', '6–3, 5–7, 6–3']
SQL:

assistant: SELECT "Opponent in the final" FROM "Table" WHERE "Surface" = 'Hard' AND "Score" = 'walkover';