CHIEF OF STAFF – The man in the middle of all things presidential – especially the health care reform legislation in Congress right now – is President Obama’s Chief of Staff Rahm Emanuel. Katie Couric talks to Obama’s right-hand man about his tough job and his even tougher reputation. Draggan Mihailovich and Jennifer Yuille are the producers. THE LOST CHILDREN OF HAITI – Scott Pelley reports on the most vulnerable victims of Haiti’s earthquake, children who not only face hunger, disease and sexual assault, but a form of slavery that is legal in the Caribbean country. Solly Granatstein and Nicole Young are the producers. TENNIS TWINS – Pro tennis’ leading doubles champions are identical twins who are so coordinated on the court that their opponents actually suspect they have twin telepathy. Lesley Stahl reports. Shachar Bar-On is the producer.