What is {employer} of {Herbert von Karajan} that is {replaced by} is {Paul van Kempen} ?
When he was replaced by Paul van Kempen, who was Herbert von Karajan's employer?
Who was Herbert von Karajan employed by when he was replaced by Paul van Kempen?
SELECT ?r WHERE { resource:Herbert_von_Karajan property:employer ?o . ?o property:replaced_by resource:Paul_van_Kempen . ?o property:employer ?r }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q154895> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P108> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P1366> <http://wikidata.dbpedia.org/resource/Q529444>
} 

SELECT ?obj WHERE { wd:Q154895 p:P108 ?s . ?s ps:P108 ?obj . ?s pq:P1366 wd:Q529444 }