Which is more befitting: to pay off my father's debt of 13,000 Riyals, or to donate to the needy in Syria, knowing that the available amount is 14,000 Riyals?

If your father is in financial hardship, paying off his debt is better than donating to a distant person, because it is both an act of maintaining kinship ties (silat al-rahim) and charity (sadaqah (definition)). However, if your father is well-off and there is someone in greater need, then donating to that person is better, such as the displaced people of Syria. It is commendable to start with the closest relatives when giving charity, unless others are in greater need, in which case they should be prioritized. Charity given to a person in dire necessity is multiplied manifold.