If you have no dba-rights with your current working scheme but you want see all workspaces with its applications and parsing schemata then you have two options.
First, select the WWV_FLOWS table. This table is owned by the Apex owner scheme, like apex_040200 (for apex 4.2.x).
You need a grant before you retrieve WWV_FLOWS table:
GRANT SELECT ON apex_040200.wwv_flows TO [PARSING_SCHEME];
SELECT * FROM apex_040200.wwv_flows;
Second possibility with the following grant:
GRANT apex_administrator_role TO [PARSING_SCHEME];
Then you can see your desired result with:
SELECT * FROM APEX_APPLICATIONS;
With these two options you can find a summary of all your applications, no matter what workspaces they are.
To find out your parsing scheme inside the Application Builder navigate to Application Properties, section Security and there in Database Session.
or submit this SQL:
SELECT sys_context('USERENV', 'CURRENT_SCHEMA') FROM DUAL;