Correspondent Byron Pitts has been covering New Orleans since Hurricane Katrina devastated the area in 2005. His very first "60 Minutes" report, in 2006, was about then-Mayor Ray Nagin, as he struggled to get the city back on its feet. While many say Nagin ultimately failed, there's a new mayor giving the city new hope: Mitch Landrieu. What's different about Landrieu? And, perhaps more importantly, how did he get Byron to put on a clown costume and ride atop a Mardi Gras float?