CREATE TABLE table_20440 ("Engine type" TEXT, "Scenario" TEXT, "SFC in lb/ ( lbf\\u00b7h ) " TEXT, "SFC in g/ ( kN\\u00b7s ) " TEXT, "Specific impulse  ( s ) " FLOAT, "Effective exhaust velocity  ( m/s ) " FLOAT)

What is the SFC when the specific impulse is 453?
SELECT "SFC in g/(kN\u00b7s)" FROM table_20440 WHERE "Specific impulse (s)" = '453'
SELECT "SFC in g/(kN\u00b7s)" FROM "table_20440" WHERE "Specific impulse (s)" = '453'