CREATE TABLE table_64776 ("Year" FLOAT, "Category" CLOB, "Recipients and nominees" CLOB, "Role/Episode" CLOB, "Result" CLOB)

What's the category in 1998 with the role/episode of David Duchovny?
SELECT "Category" FROM table_64776 WHERE "Year" = '1998' AND "Role/Episode" = 'david duchovny'
SELECT "Category" FROM "table_64776" WHERE "Role/Episode" = 'david duchovny' AND "Year" = '1998'