What is the first and last name of the artist who performed back stage for the song 'Der Kapitan'?
CREATE TABLE tracklists (
    albumid number,
    position number,
    songid number
)

CREATE TABLE instruments (
    songid number,
    bandmateid number,
    instrument text
)

CREATE TABLE songs (
    songid number,
    title text
)

CREATE TABLE band (
    id number,
    firstname text,
    lastname text
)

CREATE TABLE performance (
    songid number,
    bandmate number,
    stageposition text
)

CREATE TABLE albums (
    aid number,
    title text,
    year number,
    label text,
    type text
)

CREATE TABLE vocals (
    songid number,
    bandmate number,
    type text
)
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"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the first and last name of the artist who performed back stage for the song 'Der Kapitan'? ### Input: CREATE TABLE tracklists (
    albumid number,
    position number,
    songid number
)

CREATE TABLE instruments (
    songid number,
    bandmateid number,
    instrument text
)

CREATE TABLE songs (
    songid number,
    title text
)

CREATE TABLE band (
    id number,
    firstname text,
    lastname text
)

CREATE TABLE performance (
    songid number,
    bandmate number,
    stageposition text
)

CREATE TABLE albums (
    aid number,
    title text,
    year number,
    label text,
    type text
)

CREATE TABLE vocals (
    songid number,
    bandmate number,
    type text
) ### Response: 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"