CREATE TABLE table_4557 ("Actor/actress" TEXT, "Character" TEXT, "Rank" TEXT, "Tenure" TEXT, "Episodes" TEXT)

What years were actress Nadine Garner on the show?
SELECT "Tenure" FROM table_4557 WHERE "Actor/actress" = 'nadine garner'
SELECT "Tenure" FROM "table_4557" WHERE "Actor/actress" = 'nadine garner'