I have a 1 1/2 year old lab mix who recently started humpig my leg whenever she gets the chance and she gets aggressive when I try to pull her off she is not spayed because we breed her what do I do

Leg humping can be the result of several things, the main one and most common being a dominance issue.

Do you do obedience with your dogs? Obedience is a great way to establish yourself as the pack leader as well as working as a bonding exercise.
Basic obedience consists of just simple commands (sit, stay, come etc) but more importantly it teaches your dog to listen to you and shows that you are above them on the ladder.

Some dogs will hump due to sexual "desire", all dogs have the instinct to reproduce and some times they get a little confused at the process.

I would start with the obedience classes and in conjunction with that you need to reprimand her when she humps, without being bitten.
I would suggest a squirt bottle with water, and every time she tries to hump your leg, give her a squirt and stand up and walk away.

Now to address the breeding issue...
I am hoping you meant "intended" to be a breeding dog, not that she already is one. At 1 1/2 years of age she isn't old enough to have had accurate hip and elbow scores done yet.
The results will not be accurate until 2 years of age.
There are many other tests to be completed as well but I'm sure you already know about those.

What is your intention with allowing a cross-bred dog to breed, what attributes does she have to improve the next generation? Is she a certified working dog? Agility champion?

ADD - I hope this is not the rescue dog you previously posted about!

I agree with the dominence issue. There isn't much more I can add to what Shazzy has said. Please have your dog spayed. She is not a registered breed, and she has no business breeding at such a young age. If you are not going to the proper testing before hand, you (I'm sorry to be harsh) are no better than a back yard breeder or a puppy mill. Breeders very rarely make money off litters, they breed for the love of a wonderful bloodline.

Millions of puppies and dogs die each year in North America due to un wanted litters and products of puppy mills and BYB. Please re consider breeding your dog. Please.

I say dominance issues as well..