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

What is the first and last name of the artist who performed back stage for the song 'Der Kapitan'?
SELECT T2.firstname, T2.lastname FROM performance AS T1 JOIN band AS T2 ON T1.bandmate = T2.id JOIN songs AS T3 ON T3.songid = T1.songid WHERE T3.title = "Der Kapitan" AND T1.stageposition = "back"
SELECT "T2"."firstname", "T2"."lastname" FROM "performance" "T1" JOIN "band" "T2" ON "T1"."bandmate" = "T2"."id" JOIN "songs" "T3" ON "Der Kapitan" = "T3"."title" AND "T1"."songid" = "T3"."songid" WHERE "T1"."stageposition" = "back"