Postgres 9.3 changes the standard_conforming_strings value
How exactly did you set standard_conforming_strings?

If you did that in your session, it only applies to that session. For a permanent setting change your postgresql.conf and reload.

Also, a pg_dump  cannot reveal anything. The setting in the dump only applies to the dump. To see the current setting of your database, run

SHOW standard_conforming_strings;


Or:

SELECT * FROM pg_settings WHERE name = 'standard_conforming_strings';


Here you also see where the current value is from and whether it's the default etc.

Generally, It's a very bad idea to try and keep standard_conforming_strings off. This was changed for a good reason. It's going to bite you sooner or later. Update to the current (superior) standard.