Hey @abhi, great question! Whether 3 is a time or a number of pizza slices, and whether it means 3pm or 3am, depends on the context. And Duckling doesn’t know this context, so it can’t help you directly 
What you can do is to extract not just times but also numbers with Duckling (i.e. dimensions: ["time", "number", ...]. Assuming your bot asks about the time within a form, you’d then create a form validation action in which you can do some clever post-processing of the extracted number entity (e.g. add pm or am to it) and fill your time slot accordingly.
Let me know if this helps!