Question: Who had headed the governmental agencies whose admin HQ was in Niederkirchnerstrasse?
SPARQL:
SELECT DISTINCT ?uri WHERE { ?x <http://dbpedia.org/ontology/headquarter> <http://dbpedia.org/resource/Niederkirchnerstraße> . ?x <http://dbpedia.org/ontology/leader> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/GovernmentAgency>}