CREATE TABLE table_60179 ("Week" TEXT, "Theme" TEXT, "Song Sung" TEXT, "Artist" TEXT, "Status" TEXT)

Which song was sung by Artist Luther Vandross in the Week Top 20?
SELECT "Song Sung" FROM table_60179 WHERE "Artist" = 'luther vandross' AND "Week" = 'top 20'
SELECT "Song Sung" FROM "table_60179" WHERE "Artist" = 'luther vandross' AND "Week" = 'top 20'