Answer is in article 225 TFEU which is the only one dealing with the matter. There’s no time-limit for acting on a Parliament’s resolution, nor is there an obligation to introduce anything, at least legally speaking :
“The European Parliament may, acting by a majority of its component Members, request the
Commission to submit any appropriate proposal on matters on which it considers that a Union
act is required for the purpose of implementing the Treaties. If the Commission does not submit a
proposal, it shall inform the European Parliament of the reasons.”
The EC commited itself to answer within 3 months in a 2010 Framework agreement, yet this is not legally binding in the sense that it is not the document that could be judicially enforced by the ECJ in case of non compliance with the principles set in it. Yet I do think that when taking action to enforce a legal document is not an option, the legal document should not, as a matter of fact, be viewed as legally binding. It’s more of a gentleman’s agreement, not more.