Had sex on 13th had cycle on 14th had sex on 19th with 2 different guys bouth unprotected so which date did I conceive

Honestly, it could have been either the 13th or the 19th.

Statistically, though, it is harder to get pregnant right before your period. YET, it is possible to get pregnant right before and even during your period. (Sperm can live 3 days or more in a woman's body... if your body releases an egg while you have sperm to impregnate it, chances are, you'll get pregnant. Some women may also have light bleeding, "spotting", while pregnant as the egg is being inserted into the uterine wall, see http://www.emedicinehealth.com/pregnancy_bleeding/article_em.htm and another similar thread can be found at http://womenshealth.about.com/b/2003/08/06/period-during-pregnancy.htm)

If you actually DID have a period on the 14th (and not just light bleeding/spotting), then more likely, you got pregnant on the 19th as most women's bodies release an egg towards the middle of their cycle.

Only a DNA test will definitely show who the father is, however.

You wouldn't have had a period if you had conceived on the 13th