What would happen if there was a gas canister leaking in the same room as an open flame?

Imagine there was a gas canister that was leaking in a closed room with a lit candle. What would happen? I assume that gas is heavier/lighter than regular air and thus would pool up untill it reached the flame and create a large reaction. But what if the air was constantly being mixed and the gas dissipated evenly? Would small parts of ut just burn off constantly? Would everything eventually go up in flames? Just curious.