In Sybase Adaptive Server Enterprise (ASE) you can use CONVERT function to convert an expression (a string i.e.) to TIME data type. In PostgreSQL you can to use CAST or various type conversion functions.
Sybase ASE:
-- Convert string to TIME SELECT CONVERT(TIME, '11:11'); # 11:11:00 AM
PostgreSQL:
-- Convert string to TIME SELECT CAST( '11:11' AS TIME); # 11:11:00
For more information, see Sybase ASE to PostgreSQL Migration