Cooking time for steaming vegetables "Al Dente'?
Here's a guide to steaming times for vegetables.

From that guide your ingredients take:


peas, sugar snap, whole pea pods, trimmed - 5-6 minutes
beans, whole - 6-10 minutes
broccoli, trimmed stalks split in half or florets - 5-7 minutes
leeks, trimmed, cut in half - 5-8 minutes


As you can see, there's a bit of variation here in time but (assuming you're not talking about shelled peas or snow peas), it looks like 5-7 minutes should be a good starting goal. 

You might be prepared to pull the peas out early or maybe start them a bit later. Unfortunately, it's a matter of taste, so times really are very flexible. With a mix like this, you're likely going to need to be willing to have some of the vegetables a bit soft and some a bit hard but some textural variation should be nice as one texture can get a bit monotonous after a while anyway.

Note, though, if your leeks are cut smaller than this, particularly if they fall apart into rings or half rings, they will likely take considerably less time to steam.