What is {population} of {Rouen} that is {point in time} is {2013-1-1} ?
What was the population of Rouen in 2013?
Mention the population of Rouen at the time of 2013?
SELECT ?g WHERE { resource:Rouen property:population ?r . ?r property:point_in_time ?s . FILTER ( CONTAINS ( YEAR ( ?s ) , '2013' ) ) . ?r property:population ?g }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q30974> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P1082> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P585> <2013-1-1>
} 

SELECT ?obj WHERE { wd:Q30974 p:P1082 ?s . ?s ps:P1082 ?obj . ?s pq:P585 ?x filter(contains(YEAR(?x),'2013')) }