query: SELECT ?item (GROUP_CONCAT(DISTINCT(?delabel)) as ?delabels) (GROUP_CONCAT(DISTINCT(?enlabel)) as ?enlabels) WHERE 
  {  
    ?item wdt:P31/wdt:P279* wd:Q21191270 .
    ?item wdt:P179 wd:Q210146.   
    #?item wdt:P361 ?season .
    #?season p:P179 ?season_statement .
    #?season_statement pq:P1545 ?nr_s  .
    #?item p:P179 ?episode_statement .
    #?episode_statement pq:P1545 ?nr_e  .
    OPTIONAL { ?item rdfs:label ?enlabel . FILTER(lang(?enlabel)="en")  } 
    OPTIONAL { ?item rdfs:label ?delabel . FILTER(lang(?delabel)="de")  }  
  } GROUP BY ?item ?qid