CREATE TABLE table_48931 ("Year" FLOAT, "Category" TEXT, "President" TEXT, "Nominee" TEXT, "Film or Television Series or Miniseries" TEXT)

In what year was Martin Sheen nominated?
SELECT "Year" FROM table_48931 WHERE "Nominee" = 'martin sheen'
SELECT "Year" FROM "table_48931" WHERE "Nominee" = 'martin sheen'