user: Question: How many appointed archbishops were ordained as priests on December 20, 1959
Columns: ['Archbishop', 'Born', 'Ordained Priest', 'Ordained Bishop', 'Appointed Archbishop', 'Vacated throne', 'Died']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Jean Baptiste Lamy', 'October 11, 1814', 'December 1838', 'November 24, 1850', 'February 12, 1875', 'August 18, 1885', 'February 13, 1888']
SQL:

assistant: SELECT COUNT("Appointed Archbishop") FROM "Table" WHERE "Ordained Priest" = 'December 20, 1959';