Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "The number of the people of Badr was three hundred and thirteen. The Muhajirun were sixty-odd, and the Ansar were two hundred and thirty-six. The standard-bearer of the Muhajirun was Sayyiduna Ali bin Abi Talib (may Allah be pleased with him), and the standard-bearer of the Ansar was Sayyiduna Sa'd bin Ubadah (may Allah be pleased with him)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12032