INSERT into forum (memberName,original) values (?,?)
  on duplicate key update forum set current=? where memberName=?
[download]

Assuming you want current set even the first time, do it with:

INSERT into forum (memberName,original,current) values (?,?,?)
  on duplicate key update forum set current=values(current) where memb
+erName=?
[download]

if you wanted a perl solution instead (e.g. if the DB engine you're using appears not to enforce the uniqueness constraint), the idea would be to do a select first on the "contest" table for the given memberName value; if that returns a non-empty value, update the "current" field for that row; otherwise, insert a new row.

The select is redundant; try the update, and if it processes no rows, try the insert.

Better yet, if the database engine you're using doesn't enforce a uniqueness constraint, get a better database system.