CREATE TABLE table_73673 ("Season" FLOAT, "Series" TEXT, "Team" TEXT, "Races" FLOAT, "Wins" FLOAT, "Poles" FLOAT, "F/Laps" FLOAT, "Podiums" FLOAT, "Points" FLOAT, "Position" TEXT)

How many podiums when he was in the british f3 national class series?
SELECT COUNT("Podiums") FROM table_73673 WHERE "Series" = 'British F3 National Class'
SELECT COUNT("Podiums") FROM "table_73673" WHERE "Series" = 'British F3 National Class'