What is {employer} of {Herbert von Karajan} that is {replaced by} is {Paul van Kempen} ?
Who was Herbert von Karajan employed by when he was replaced by Paul van Kempen?
SELECT ?obj WHERE { wd:Q154895 p:P108 ?s . ?s ps:P108 ?obj . ?s pq:P1366 wd:Q529444 }
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>
} 

When he was replaced by Paul van Kempen, who was Herbert von Karajan's employer?