CREATE TABLE table_2633 ("District" TEXT, "Vacator" TEXT, "Reason for change" TEXT, "Successor" TEXT, "Date successor seated" TEXT)

How many date of successor seated is new jersey 2nd in the district?
SELECT COUNT("Date successor seated") FROM table_2633 WHERE "District" = 'New Jersey 2nd'
SELECT COUNT("Date successor seated") FROM "table_2633" WHERE "District" = 'New Jersey 2nd'