CREATE TABLE table_75032 ("Call sign" TEXT, "Analog channel" TEXT, "Digital channel" TEXT, "Virtual channel" TEXT, "Network" TEXT, "Station Ownership" TEXT)

Network of nbc is what digital channel?
SELECT "Digital channel" FROM table_75032 WHERE "Network" = 'nbc'
SELECT "Digital channel" FROM "table_75032" WHERE "Network" = 'nbc'