query: SELECT ?item ?start ?groupLabel ?districtLabel ?replacesLabel WHERE {
  ?item wdt:P31 wd:Q5;
        p:P39 ?position.
  ?position ps:P39 wd:Q10655178;
            pq:P580 ?start.
  OPTIONAL { ?position pq:P582 ?end }
  OPTIONAL { ?position pq:P4100 ?group }  
  OPTIONAL { ?position pq:P768 ?district }
  OPTIONAL { ?position pq:P1365 ?replaces }  
  FILTER (!BOUND(?end))  
    SERVICE wikibase:label { bd:serviceParam wikibase:language "[AUTO_LANGUAGE],en". }
  }