Error in using bind variables in tablespace creation script

[balasmg]

my purpose is to get the path of the datafile from v$datafile and use the same to create a tablespace in that path.

this to be run in a script.

VAR TSP VARCHAR2(200);

SELECT '''' || SUBSTR(NAME,1,INSTR(NAME,'/',-1)) ||'demodata01.DBF'''
into :tsp
FROM V$DATAFILE
WHERE ROWNUM < 2;


--ACCEPT tsp PROMPT 'Enter the Datafile Location and Name:'

PROMPT PL. WAIT...! TABLE SPACE CREATION IN PROGRESS...!

exec execute immediate 'CREATE TABLESPACE demodata DATAFILE' || :tsp || ' SIZE 2048 M EXTENT MANAGEMENT LOCAL';

I GET THE FOLLOWING ERROR

ERROR at line 1:
ORA-02236: invalid file name
ORA-06512: at line 1

PL. LET ME KNOW THE SCRIPT