SELECT * FROM V$TEMP_EXTENT_MAP;

TABLESPACE_NAME                FILE_ID    BLOCK_ID   BYTES      BLOCKS     OWNER      RELATIVE_F
------------------------------ ---------- ---------- ---------- ---------- ---------- ----------
TEMPORARY_DATA                          1          9    1048576        128          1          1
TEMPORARY_DATA                          1        137    1048576        128          1          1
TEMPORARY_DATA                          1        265    1048576        128          1          1
TEMPORARY_DATA                          1        393    1048576        128          1          1
TEMPORARY_DATA                          1        521    1048576        128          1          1
TEMPORARY_DATA                          1        649    1048576        128          1          1

etc ...