what are the poll respondent categories that exist in the first election poll?
Entity
m.0m3jn3g
Registered Voters
class class literal
government.poll_respondent_category government.election_poll 0^^http://www.w3.org/2001/XMLSchema#int
government.poll_respondent_category government.election_poll type.datetime
Poll respondent category Election poll 0
none none argmin
government.poll_respondent_category.polls government.election_poll.poll_end_date
Polls Poll end date
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :government.poll_respondent_category . 
?x1 :type.object.type :government.election_poll . 
{
SELECT (MIN(?y2) AS ?x2)  WHERE { 
?y0 :type.object.type :government.poll_respondent_category . 
?y1 :type.object.type :government.election_poll . 
?y0 :government.poll_respondent_category.polls ?y1 . 
?y1 :government.election_poll.poll_end_date ?y2 . 
FILTER ( ?y0 != ?y1 && ?y0 != ?y2 && ?y1 != ?y2  )
}
}
?x0 :government.poll_respondent_category.polls ?x1 . 
?x1 :government.election_poll.poll_end_date ?x2 . 
FILTER ( ?x0 != ?x1 && ?x0 != ?x2 && ?x1 != ?x2  )
}
}
(ARGMIN government.poll_respondent_category (JOIN government.poll_respondent_category.polls government.election_poll.poll_end_date))