What are the names of the songs without a lead vocal?
SELECT DISTINCT title FROM vocals AS t1 JOIN songs AS t2 ON t1.songid  =  t2.songid EXCEPT SELECT t2.title FROM vocals AS t1 JOIN songs AS t2 ON t1.songid  =  t2.songid WHERE TYPE  =  "lead"
Baş vokal olmadan şarkıların isimleri nelerdir?