user: Question: When was the last year when Katharine Hepburn won?
Columns: ['Superlative', 'Actress', 'Record Set', 'Year', 'Notes']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Most Awards', 'Katharine Hepburn', '4 awards', 1981.0, 'Awards resulted from 12 nominations.']
SQL:

assistant: SELECT MAX("Year") FROM "Table" WHERE "Actress" = 'Katharine Hepburn';