CREATE TABLE table_202_115 (id NUMBER, "station" CLOB, "distance from wellington" CLOB, "height above sea level  ( m ) " CLOB, "opened" CLOB, "closed" CLOB, "notes" CLOB)

how much higher is the takapu road station than the wellington station ?
SELECT (SELECT "height above sea level (m)" FROM table_202_115 WHERE "station" = 'takapu road') - (SELECT "height above sea level (m)" FROM table_202_115 WHERE "station" = 'wellington')
SELECT (SELECT "height above sea level (m)" FROM "table_202_115" WHERE "station" = 'takapu road') - (SELECT "height above sea level (m)" FROM "table_202_115" WHERE "station" = 'wellington')