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

Who is performing in the back stage position for the song 'Der Kapitan'? Show the first name and last name.
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"