Molly is in my White Forest at the moment, and I'm trying to catch an Azurill. I've been running through grass for about 20-30 minutes, and all I get are Rhyhorns, Hoppips and Wurmples (corresponding to the three other NPCs in my White Forest right now).
So do I just have bad luck?
Yeah, you're just incredibly unlucky. 45 minutes is a ridiculous amount of time.
Do you have Pokemon Black/White 2? If so, you can find Azurill in Floccessy Ranch pretty frequently. Catch one and trade it over to your White version. You can always keep trying, but it looks like the Ranch will be quicker, those Azurills at White Forest are giving you a hard time. :/
Have you used surf on the pool of water?If you have try running through different patches of grass instead of one patch.