Ukrainian candidates Volodymyr Zelensky and incumbent President Petro Poroshenko cast their ballot in the second round of the country's presidential election. Forty-one-year-old Volodymyr Zelensky's bid to lead the country of 45 million people was initially dismissed as a joke when he announced his candidacy on New Year's Eve. But now all opinion polls suggest incumbent President Petro Poroshenko is heading for defeat amid widespread anger over poverty, corruption and war.