Possible Clues:

• Gershwin operatic heroine
• Mamie's predecessor in the White House
• Catfish Row opera heroine
• "The Highwayman" daughter
• Harry's First Lady
• 'Porgy and --', opera by George Gershwin
• "Summertime" singer
• Myerson who was the city's first Commissioner of Consumer Affairs
• 1940s-'50s White House name
• 2012 Broadway role for Audra McDonald