user: Question: In what year did the team of aston martin racing have a position of 6th?
Columns: ['Year', 'Team', 'Co-Drivers', 'Class', 'Laps', 'Pos.', 'Class Pos.']
Types: ['real', 'text', 'text', 'text', 'real', 'text', 'text']
Sample row: [2005.0, 'Rollcentre Racing', 'Michael Krumm Bobby Verdon-Roe', 'LMP1', 133.0, 'DNF', 'DNF']
SQL:

assistant: SELECT "Year" FROM "Table" WHERE "Team" = 'aston martin racing' AND "Pos." = '6th';