what is the {start time} for {Xi'an} has {twinned administrative body} as {Dortmund} ?
Give me the start time for Xi'an has twinned administrative body as Dortmund ?
SELECT ?value WHERE { wd:Q5826 p:P190 ?s . ?s ps:P190 wd:Q1295 . ?s pq:P580 ?value}
select distinct ?value  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q5826> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P190> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> <http://wikidata.dbpedia.org/resource/Q1295> .
?statement <http://www.wikidata.org/entity/P580> ?value. 
} 

What is the start time for Xi'an has paired administrative body as Dortmund ?