CREATE TABLE table_48890 ("Season" TEXT, "Duration" TEXT, "Gagarin Cup Winner" TEXT, "Gagarin Cup finalist" TEXT, "Continental Cup Winner" TEXT, "Top scorer" TEXT)

Who is the gagarin cup winner when avangard omsk is the gagarin cup finalist?
SELECT "Gagarin Cup Winner" FROM table_48890 WHERE "Gagarin Cup finalist" = 'avangard omsk'
SELECT "Gagarin Cup Winner" FROM "table_48890" WHERE "Gagarin Cup finalist" = 'avangard omsk'