user: Question: What is the Season when the Opponent was Zenit St. Petersburg?
Columns: ['Season', 'Competition', 'Round', 'Opponent', 'Series']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['2002–03', 'UEFA Cup', 'R1', 'Zenit St. Petersburg', '4–3']
SQL:

assistant: SELECT "Season" FROM "Table" WHERE "Opponent" = 'Zenit St. Petersburg';