CREATE TABLE table_50723 ("Line" TEXT, "Operator" TEXT, "Line length  ( kilometres ) " FLOAT, "Number of stations" FLOAT, "Annual ridership  ( 1998 ) " FLOAT, "Annual ridership  ( 2008 ) " FLOAT)

Which Annual ridership (2008) has a Number of stations larger than 70, and an Annual ridership (1998) smaller than 451,971,849?
SELECT MIN("Annual ridership (2008)") FROM table_50723 WHERE "Number of stations" > '70' AND "Annual ridership (1998)" < '451,971,849'
SELECT MIN("Annual ridership (2008)") FROM "table_50723" WHERE "Annual ridership (1998)" < '451,971,849' AND "Number of stations" > '70'