What is {position held} of {Donald Tusk} that is {replaces} is {Herman Van Rompuy} ?
What was Donald Tusk's position before he was replaced by Herman Van Rompuy ?
What was Donald Tusk's position that was replaced by Herman Van Rompuy?
SELECT ?q WHERE { ?p property:position_held ?q . resource:Donald_Tusk property:position_held ?p . ?p property:replaces resource:Herman_Van_Rompuy }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q946> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P39> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P1365> <http://wikidata.dbpedia.org/resource/Q12983>
} 

SELECT ?obj WHERE { wd:Q946 p:P39 ?s . ?s ps:P39 ?obj . ?s pq:P1365 wd:Q12983 }