query: SELECT ?item (GROUP_CONCAT(DISTINCT(?delabel)) as ?delabels) (GROUP_CONCAT(DISTINCT(?enlabel)) as ?enlabels) ?nr_s ?nr_e WHERE 
  {  
    ?item wdt:P31/wdt:P279* wd:Q21191270 .
    ?item wdt:P179 wd:Q218567.   
    OPTIONAL {
       ?item wdt:P4908 ?season .
       ?season p:P179 ?season_statement .
       ?season_statement pq:P1545 ?nr_s  .
       ?item p:P4908 ?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 ?nr_s ?nr_e
  ORDER BY xsd:integer(?nr_s) xsd:integer(?nr_e)