CREATE TABLE table_65856 ("Year  ( Ceremony ) " TEXT, "Actor/Actress" TEXT, "Category" TEXT, "Film title used in nomination" TEXT, "Result" TEXT)

What is the year when sigourney weaver was nominated for best actress?
SELECT "Year (Ceremony)" FROM table_65856 WHERE "Category" = 'best actress' AND "Actor/Actress" = 'sigourney weaver'
SELECT "Year (Ceremony)" FROM "table_65856" WHERE "Actor/Actress" = 'sigourney weaver' AND "Category" = 'best actress'