ANSWER:
There is Zakat on it if it finishes one lunar year from the day displayed till the day the new House was bought.
For example, if you displayed it for sale on 1st of Muharram and it was sold in Ramadan and you kept the money till the following Muharram, you must give zakat. But if you bought the new house before it finished a lunar year, there is no zakat on it.