JOHANNESBURG — Nelson Mandela is spending a thirteenth day in a South African hospital after being diagnosed with a lung infection and undergoing gallstone surgery. Presidential spokesman Mac Maharaj said Thursday that there is no update on the medical status of the anti-apartheid icon, who was admitted Dec. 8 to a hospital in the capital, Pretoria. On Tuesday, President Jacob Zuma said 94-year-old Mandela required “extraordinary care” due to his age. — AP