By Khalil Ashawi DAMASCUS, July 12 (Reuters) - Syria's new parliament convened for the first time on Sunday, 19 months after rebels led by President Ahmed al-Sharaa toppled Bashar al-Assad, a milestone in the country's political transition despite the chamber's current limited powers. Sharaa, in a speech at parliament in Damascus, told lawmakers to "make this council a model of responsibility and competence" and described it as "a platform for truth and justice".