what is the {start time} for {Bern} has {head of government} as {Alexander Tschäppät} ?
When did Alexander Tschappat begin his role as the head of government of Bern?
Since what time Bern has the head of government as Alexander Tschäppät?
SELECT ?n WHERE { ?q property:head_of_government resource:Alexander_Tschäppät . ?q property:start_time ?n . resource:Bern property:head_of_government ?q }
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q70> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P6> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q74144> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

SELECT ?value WHERE { wd:Q70 p:P6 ?s . ?s ps:P6 wd:Q74144 . ?s pq:P580 ?value}