Charlie Rose interviews Syrian president Bashar al-Assad. Also: Scott Pelley speaks with Barack Obama about chemical weapons use in Syria; John Miller questions former CIA deputy director Michael Morell about the crisis in Syria. Steve Kroft reports on the business of growing and selling medical marijuana in Colorado.

Charlie Rose interviews Syrian President Bashar al-Assad as Syria's four-year-old civil war drags on; and, 60 Minutes follows brain cancer patients in a Duke University clinical trial of a therapy that uses a re-engineered polio virus to kill cancer cells.