roundup
Roundup is a NON SELECTIVE, herbicide. It will kill anything when applied at the recommended rate. Roundup doesn't work as well on quack grass and like any type of herbicide it will not work well on anything that has gone to a seedhead. Herbicides also don't work as well on anything understress or when plants are dormant.
To kill grasses in clovers and legumes, use poast, select, arrow and other grass herbicides. Consult with an agronomist for more detailed answers when in doubt.
I helped bring generic roundup into the United states years back and am very very fluent in roundup/generic roundup use and other chemical questions.
There are products like buctril, brox and other products that i do use when the legumes are dormant, late fall or early spring during early growth but for the novice applicator, i wouldn't recommend rolling the dice with them , unless your use to working with chemicals and have the knowlege on timing your application.