user: Question: How many of the episodes in the top 50 rankings were originally aired on June 28, 2010?
Columns: ['Episode number', 'Title', 'Original airing', 'Timeslot', 'Viewers', 'Top 50 Ranking', 'Scripted Show Ranking']
Types: ['real', 'text', 'text', 'text', 'real', 'real', 'real']
Sample row: [112.0, 'Nice Is Different Than Good', 'February 15, 2010', '8:35pm – 9:30pm', 479100.0, 12.0, 3.0]
SQL:

assistant: SELECT COUNT("Top 50 Ranking") FROM "Table" WHERE "Original airing" = 'June 28, 2010';