If I were to have asked you which door is the Escape Door, what would you have said?

>You are a captive in a far away land. The king offers you you freedom if you can pass the following test:
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>You are to be placed in a room with two doors. Behind one door is a ferocious tiger, behind the other is your escape. 30 feet above each door is a window where a man is sitting. One man always tells the truth, the other is an incessant liar. You may ask only one question.
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>To ensure your safe passage, what should your question be?