According to the AVR Instruction Set Manual:
The STS command "store direct to data space" moves the contents of a register to the given address. A hex value is put into the register first using the LDI command. The opcode for the STS instruction is 32 bits long. 16 bits of it are used for the data space address.
The OUT command, "Stores data from register Rr in the Register File to I/O Space (Ports, Timers, Configuration Registers, etc". It would be used to put a value from a register into the OCR0 register, not the STS command.