user: Question: what's the earliest year that the Wimbledon opponent was Zheng Jie?
Columns: ['Aces', 'Player', 'Opponent', 'Year', 'Event', 'Sets', 'Result']
Types: ['real', 'text', 'text', 'real', 'text', 'real', 'text']
Sample row: [25.0, 'Alexandra Stevenson', 'Alexandra Mueller', 2013.0, 'Quebec City', 3.0, '7–6 (9–7) , 6–7 (3–7) , 6–7 (9–11)']
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Event" = 'Wimbledon' AND "Opponent" = 'Zheng Jie';