The packed house at Sampan (124 S. 13th) Thursday night didn't seem to notice that rock legend Robert Plant was in the restaurant. But the Led Zeppelin frontman had broccoli, Brussels sprouts and potstickers and sipped Ciroc straight-up on his second visit to Sampan in days. Plant, who played the Tower Theatre Wednesday with his Band of Joy, was recognized by a few fans Thursday afternoon on 13th and Sansom where he stopped to take some pictures.