List the leaders of all the cities through which the Ganga river flows ?
SELECT DISTINCT ?uri WHERE { <http://dbpedia.org/resource/Ganges> <http://dbpedia.org/property/city> ?x . ?x <http://dbpedia.org/ontology/leaderName> ?uri  . ?x <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://dbpedia.org/ontology/City>}
Ganges