PREFIX pub: <http://ontology.ontotext.com/taxonomy/>
PREFIX publishing: <http://ontology.ontotext.com/publishing#>

select ?personLabel ?party_name ?document (?mention as ?men) where {
    ?mention publishing:hasInstance ?person .
    ?document publishing:containsMention ?mention .
    ?person pub:memberOfPoliticalParty ?party .
    ?person pub:preferredLabel ?personLabel .
    ?party pub:hasValue ?value .
    ?value pub:preferredLabel ?party_label .
    Bind(?party_label as ?party_name)
} order by ?mention