CREATE TABLE table_204_711 (id DECIMAL, "dance" TEXT, "best dancer ( s ) " TEXT, "best score" DECIMAL, "worst dancer ( s ) " TEXT, "worst score" DECIMAL)

which dance is previous to tango
SELECT "dance" FROM table_204_711 WHERE id = (SELECT id FROM table_204_711 WHERE "dance" = 'tango') - 1
SELECT "dance" FROM "table_204_711" WHERE "id" = (SELECT "id" FROM "table_204_711" WHERE "dance" = 'tango') - 1