Mention the year span and the reason of service elimination of John Hume  during serving as Member of the 1st Northern Ireland Assembly
SELECT ?value1 ?value2 WHERE { wd:Q193630 p:P39 ?s . ?s ps:P39 wd:Q37303731 . ?s pq:P2715 ?value1 . ?s pq:P1534 ?value2 }
john hume: Q193630 member of the 1st northern ireland assembly: Q37303731