query: SELECT DISTINCT ?city ?cityLabel ?mayor ?mayorLabel 
  WHERE 
  {
  	?city wdt:P31/wdt:P279* wd:Q515 .  # find instances of subclasses of city
  	?city p:P6 ?statement .            # with a P6 (head of goverment) statement
  	?statement ps:P6 ?mayor .           # ... that has the value ?mayor
  	?mayor wdt:P21 wd:Q6581072 .       # ... where the ?mayor has P21 (sex or gender) female
  	FILTER NOT EXISTS { ?statement pq:P582 ?x }  # ... but the statement has no P582 (end date) qualifier	 
  	# Now select the population value of the ?city
  	# (wdt: properties use only statements of "preferred" rank if any, usually meaning "current population")
  	?city wdt:P1082 ?population .
  	# Optionally, find English labels for city and mayor:
  	SERVICE wikibase:label {
  		bd:serviceParam wikibase:language "en" .
  	}
  }
  ORDER BY DESC(?population)
  LIMIT 10