Prices of oil were down in Asian transactions on Thursday, amid expectations of a Greek vote plan on bailout package scheduled for December could prompt Greece to exit from the Euro zone.In Singapore, US light crude for December delivery was down to USD 1.07 per barrel (pb) to come at USD 91.44 a barrel in electronic trading on the New York Mercantile Exchange (NYMEX). The contract rose USD 32 cents to settle at USD 92.51 in New York late Wednesday.In London, Brent crude was down USD 12 cents to come at USD 108.55 a barrel.Germany and France called on Greece late Wednesday to necessarily determine its position of whether staying in the Euro zone or not in next mid-December through voting on bailout package estimated at Euro 130 billion, which the European Union approved last week.Both German Chancellor Angela Merkel and French President Nicolas Sarkozy called on Greek Prime Minister George Papandreou to hold talks on the issue before the G20 summit in Cannes in order to resolve the Greek crisis quickly.In other NYMEX trading, heating oil fell USD 1.2 cents to come at USD 2.99 per gallon, while gasoline futures slid USD 2.1 cents at come at USD 2.61 per gallon. Meanwhile, natural gas added USD 1.9 cents to come at USD 3.77 per 1, 000 cubic feet.