user: Question: Which Years have a Character of Dr Trevor Stewart?
Columns: ['Character', 'Actor', 'Years', 'Series', 'Episode Count']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Dr Nikki Alexander', 'Emilia Fox', '2004-', '8.5-', 86.0]
SQL:

assistant: SELECT "Years" FROM "Table" WHERE "Character" = 'Dr Trevor Stewart';