Search by country for Pakistan, and click on "Generate Data Subset" for machine readable data. Data on the 2002 and 2008 elections is available for Pakistan
Inter-parliamentary Union page on the Pakistan National Assembly, with tabs devoted to general information, the electoral system, details on the last elections (2008), and an historical election archive
Inter-parliamentary Union page on the Pakistan Senate, with tabs devoted to general information, the electoral system, details on the last elections (2012), and an historical election archive