user: Question: Which Year that has Notes of DNF?
Columns: ['Year', 'Competition', 'Venue', 'Position', 'Event', 'Notes']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1995.0, 'Venice Marathon', 'Venice, Italy', '1st', 'Marathon', '2:29:11']
SQL:

assistant: SELECT "Year" FROM "Table" WHERE "Notes" = 'DNF';