user: Question: Who is the gagarin cup winner when Avangard Omsk is the gagarin cup finalist?
Columns: ['Season', 'Duration', 'Gagarin Cup Winner', 'Gagarin Cup finalist', 'Continental Cup Winner', 'Top scorer']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['2008–09', '2 September 2008 - 12 April 2009', 'Ak Bars Kazan', 'Lokomotiv Yaroslavl', 'Salavat Yulaev Ufa * (129 points)', 'Sergei Mozyakin (76 points: 34 G, 42 A)']
SQL:

assistant: SELECT "Gagarin Cup Winner" FROM "Table" WHERE "Gagarin Cup finalist" = 'Avangard Omsk';