You could ask how many miles to the point and do the math, or request a rate of descend to be able to meet the restriction (not friendly to a busy controller, as he has to do the math), or even easier, ask for a time to be level before.
The last would give an answer like "be level before time xx" or "in xx minutes", then you should be able to calculate the rate of climb/descend yourself.
That's the really oldschool answers, if your flying without FMS and whatnot....