SQL & PL/SQL

Here's two case expressions that return the same results. Which one is best? I like the second once since there's less code.

1.)

CASE columnname1
   WHEN 1
      THEN
         CASE
             WHEN columnname2 = 'N'
                THEN
                   CASE
                      WHEN columnname3 = columnname4
                         THEN 1
                      ELSE 0
                   END
             ELSE 0     
         END
   ELSE 0     
END

2.)

CASE
   WHEN columnname1 = 1
    AND columnname2 = 'N'
    AND columnname3 = columnname4
      THEN 1
   ELSE 0
END