Polls have opened in Greece's parliamentary election, the first since the country's economy ceased to be subject to strict supervision and control by international lenders who had provided bailout funds during its nearly decade-long financial crisis. The two main contenders in Sunday's vote are conservative Prime Minister Kyriakos Mitsotakis, 55, a Harvard-educated former banking executive, and 48-year-old Alexis Tsipras, who heads the left-wing Syriza party and served as prime minister during some of the financial crisis' most turbulent years. Although Mitsotakis has been steadily ahead in opinion polls, a newly introduced electoral system of proportional representation makes it unlikely that...