CREATE TABLE instruments (songid DECIMAL, bandmateid DECIMAL, instrument TEXT)
CREATE TABLE performance (songid DECIMAL, bandmate DECIMAL, stageposition TEXT)
CREATE TABLE tracklists (albumid DECIMAL, position DECIMAL, songid DECIMAL)
CREATE TABLE band (id DECIMAL, firstname TEXT, lastname TEXT)
CREATE TABLE songs (songid DECIMAL, title TEXT)
CREATE TABLE albums (aid DECIMAL, title TEXT, year DECIMAL, label TEXT, type TEXT)
CREATE TABLE vocals (songid DECIMAL, bandmate DECIMAL, type TEXT)

Which vocal type has the band mate with last name 'Heilo' played the most?
SELECT type FROM vocals AS T1 JOIN band AS T2 ON T1.bandmate = T2.id WHERE lastname = "Heilo" GROUP BY type ORDER BY COUNT(*) DESC LIMIT 1
SELECT "type" FROM "vocals" AS "T1" JOIN "band" AS "T2" ON "T1"."bandmate" = "T2"."id" WHERE "Heilo" = "lastname" GROUP BY "type" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1