Well it depends on the purpose of the money and how reputable that exchange really is. If it's funds you intend to hold for a long time then it's absolutely unsafe to hold your funds in an exchange, whether it's a reputable exchange or not. The only situation I'd advise leaving funds on a Centralised exchange is if it's funds that you have very short term plans for, or money you intend to use pretty soon, and you should make sure in that it's actually a reputable exchange. Other than this, it'll be a very foolish choice to want to leave funds on an exchange.