Dear Kaushal,
There is no such requirement to file defence documents at the time of filing of leave to defend and the court will not dismiss leave to defend simply because no documents have been filed. At the time of leave to defend, you have to just show that there are triable issues of facts and raise doubt in the mind of court. This can be done by pointing out discrepencies from the plaint and documents relied by Plaintiff.
However, if there are any documents which support the defence, you must file them and not leave any opportunity.
Regards,
Adv. Anshula Grover